I think it's pretty fair to say that almost every single iPhone owner has experienced the shock of sitting in silence only for an alert to come through to the device causing it to vibrate. That vibration is amplified when the phone is on a hard flat surface and can be difficult to get used to if it happens repeatedly. The developer of the MyVibe Cydia tweak for jailbroken devices has clearly suffered at the hands of amplified vibration and has produced this installation to allow other users to prevent it from happening in certain circumstances.